I have tried selecting the bobuino from the dropdown list of boards in the IDE and still get the same error.
The chip is breadborded on a solderless breadbord, with just supply pins connected, 16mhz xtal and RX / TX lines from the working FDI board and a 10K resistor between RESET and +ve - The power is supplied from the +5v USB feed from the FDI board (in the same way the 328P is powered). I have the DTR line connected to the RESET pin via a series 0.1uf capacitor. I've also tried taking the VREF pin to +5v too.
I've tried using the trick with a series resistor inline with the TX/RX lines. Baud set to 115200, 8bit, no parity, and 1 stop bit (although all other baud rates have been tried)
Exactly the same optibootloader is burned into all the chips from the maniacbug directory,
so selecting any of the 1284 boards from the drop down menu will work for uploading
sketches - only the pin assignments will be different. Eg, D13 [led] is chip pin 8 for Bobuino,
but chip pin 19 for other board selections.
I assume you included the 22pF caps in addition to the xtal? Have to have those too, unless
you're using a ceramic resonator.
Have you actually measured 5V on the Vcc and Reset pins?
Also, you might try the low-pass filter in the RX0 line, people are using 10K series-R and
100pF to gnd at the RX0 pin. It's possible the chip Crossroads sent is from a batch with the
RX0 noise sensitivity.
I would also try building up the Crossroads board in minimal fashion to test.
I'm having no problems with my own 1284 test boards, so it should work for you too.